1. CHE315 Pressure Drop and Friction Loss 2.10 Design Equations for Laminar and Turbulent Flow in Pipes

2. CHE315 Pressure Drop and Friction Loss 2.10 Design Equations for Laminar and Turbulent Flow in Pipes

3. CHE315 Pressure Drop and Friction Loss 2.10B PRESSURE DROP AND FRICTION LOSS IN LAMINAR FLOW Example. 2.10-1

4. CHE315 Pressure Drop and Friction Loss Fanning friction factor f for friction loss in laminar flow f is defined as drag force per wetted surface unit area (  s at the surface area) divided by the product of density times the velocity head (  v 2 /2): The drag force The wetted surface unit area

5. CHE315 Pressure Drop and Friction Loss For laminar flow only, combining equations: and Eq (2.10-2) Eq (2.10-5)

6. CHE315 Pressure Drop and Friction Loss f from Figure 2.10-3 Laminar Turbulent

7. CHE315

8. Example 2.10-3 NOTE: If velocity and diameter are both unknown, Solution should be Trial –and-error soln. (or computerized). Pressure Drop and Friction Loss

9. CHE315 Step by step procedure for trial-and error solution 1.Assume an initial value for the velocity (or the diameter) 2.Calculate the Reynolds number (and  /D) 3.From the figure 3.10-3, read the corresponding friction factor f 4.Substitute f into: 5.Compare the obtained value with the initial one 6.If values are different repeat from step2 with the obtained value Pressure Drop and Friction Loss

10. CHE315 Example 2.10-4 Example 2.10.5 Pressure Drop and Friction Loss

11. CHE315 Pressure Drop and Friction Loss For gases, the equation can be rewritten as follows: Pressure drop and friction factor in flow of gas Ideal Gas Law:

12. CHE315 Pressure Drop and Friction Loss How did we arrive to this equation? Using Ideal Gas Law; The following equation can be obtained

13. CHE315 A L A S v L v S Pressure Drop and Friction Loss K f : Turbulent: Table 2.10-1 Laminar: Table 2.10-2

14. CHE315 Pressure Drop and Friction Loss

15. CHE315 Example 2.10.6 Example 2.10.7 Pressure Drop and Friction Loss

16. CHE315 FRICTION LOSSES IN NONCIRCULAR CONDUITS The equivalent diameter D is defined as four times the hydraulic radius r H, defined as the ratio of the cross-sectional area of the channel to the wetted perimeter of the channel.: Pressure Drop and Friction Loss

17. CHE315 Calculate the equivalent diameter? Pressure Drop and Friction Loss